mips.c (mips_expand_prologue): Handle case when generating for MIPS16 and the outgoing argument area is more...

* config/mips/mips.c (mips_expand_prologue): Handle case when
generating for MIPS16 and the outgoing argument area is more than
SMALL_OPERAND. Use the frame pointer as temporary to generate the
add instruction.

From-SVN: r103519